1. Field of the Invention
This invention relates to well tools and more particularly to tools for installing and removing flow control devices, such as gas lift valves, in gas lift wells equipped with side pocket mandrels.
2. Description of the Prior Art
Gas lift operations have been practiced for many years as a means of secondary recovery of oil from wells with formation pressures insufficient to produce without added help. In gas lift operations, gas is injected into the tubing-casing annulus at the surface and is afterwards admitted into the tubing at a point below the liquid level to aerate the liquid, decrease its flowing density, and aid in lifting it to the surface. Generally, gas lift valves control the admission of gas into the tubing. Usually several gas lift valves are used in a well and are scientifically located at strategic points to assure efficiency. Normally, one of the gas lift valves does most of the work at any given time while the others remain idle. Side pocket mandrels have been used widely to house gas lift valves in offset receptacles so that any one of the gas lift valves could be removed and replaced without disturbing the other gas lift valves in the well. To install and remove gas lift valves, and the like, in side pocket mandrels, a kickover tool is used.
While side pocket mandrels and kickover tools have been known for over 30 years, a new type became known in the early 1970's when a side pocket mandrel and kickover tool for pumpdown or through flow line (TFL) wells was introduced by Otis Engineering Corporation, Dallas, Texas, assignee of application for patent by Harry E. Schwegman for Kickover Tool, Ser. No. 490,557 filed July 24, 1974, now U.S. Pat. No. 4,294,313. This kickover tool was articulated to enable it to pass through flow lines containing bends having radii as short as 60 inches. The kickover tool had a pivot arm which would actuate to a position of about 90 degrees or normal to axis of the kickover tool in order to position a gas lift valve in axial alignment with the side pocket receptacle of a side pocket mandrel. Gas lift valves could then be pushed straight into or pulled straight from such receptacle. This arrangement required less space above the receptacle and permitted shortening of the side pocket mandrel by a considerable amount.
U.S. Pat. No. 3,837,398 issued Sept. 24, 1974 to John H. Yonker for a Kickover Tool is an improvement over the kickover tool of Schwegman. Yonker provided means in his kickover tool for releasably latching the pivot arm in kickover position. The Yonker patent is assigned to Otis Engineering Corporation (supra).
The present invention is an improvement over the Schwegman and Yonker inventions. Schwegman's application Ser. No. 490,557 and Yonker's U.S. Pat. No. 3,837,398 are hereby incorporated into this present application for all purposes.
The kickover tools of both Schwegman and Yonker were operative, but in each case their pivot arm remained spring biased after a flow control device was installed in or removed from the side pocket receptacle and its outer end, understandably, suffered much wear and damage as it was dragged along the pipe wall on the return trip out of the well. Worse yet, the pivot arm being spring pressed toward extended position prevented downward travel of the kickover tool in the well tubing which precluded occasional needful manipulation and made it sometimes difficult to retrieve the kickover tool from the well. Accordingly, for several years it was desired to provide means for automatically retracting the pivot arm upon completion of the downhole work to eliminate such wear on this expensive part and to eliminate its interference, permitting downward movement of the kickover tool when needed, thus facilitating retrieval of the tool from the well. The present invention fills this long-felt need in providing means in a kickover tool of the 90-degree type which causes the pivot arm thereof to be retracted after it has done its work downhole and holds it in retracted position during the return trip out of the well. This is not found in any of the prior art devices with which applicants are acquainted.